The world's biggest hamburger chain says it will post calorie information on restaurant and drive-thru menus nationwide starting Monday. The move comes ahead of a regulation that could require major chains to post the information as early as next year.

The president of McDonald's USA said the company wants to take the step "voluntarily."

The decision to post calorie information follows the Supreme Court's decision this summer to uphold President Barack Obama's health care overhaul, which includes a regulation that would require restaurant chains with more than 20 locations to post calorie information.

The timetable for carrying out that requirement has yet to be worked out. McDonald's, based in Oak Brook, Ill., is also testing healthier options for next year, such as an Egg McMuffin made with egg whites and a whole grain muffin. The sandwich has Canadian bacon and white cheddar cheese and clocks in at 260 calories. It will be called the Egg White Delight.

The chain is also testing versions of the McWrap, which is a bigger version of its chicken Snack Wrap that is already sold in Europe. The wraps have sliced cucumbers and range from 350 calories to 580 calories.